<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>引用</title>
</head>
<body>
<script>
    //访问者设计模式
    function  add(a,b){
        a+=20;
        alert(a+b);
    }
    function suibian(a,b,cb){
        function dapaidang(aaa){
            return aaa;
        }
        function haha(cb){
            return cb;
        }
        haha(dapaidang(cb))(a,b);
    }
    suibian(87,13,add);


</script>
</body>
</html>